Line noise - ultra low upstream

Today I've ben working from home. I normally sync at ~3800 down ~930 up on o2 LLU. I am ~4.5-5 km away, 500m D-side, with a target SNR of 6dB

My downstream sync will vary, anything from 3500-4500, but with such a long line that's par for the course.

Previous today the line had been solid for a week.

Around 0930 I lost connection and found the modem cycling, syncing and then loosing sync. Whilst the downstream sync was wierdly high (3200-4500 : higher than usual), the upstream was dropping - I saw 300, ~150 and then for a while ~70.

This continued (frustratingly) through the day, with a max of around 20 minutes stability.

Late morning I tested the analogue phone line (with a 1990s British telecom corded unpowered pushbutton handset) and noticed crackle. Somewhat intermittent. Quite for a minute or to then lots of crackling for 20-30s, then quiet. Occasional (quiet) clicks and (very quiet) crosstalk (ringback). i suspect only the shuffling crackling noise was that noticeable.

I also heard a very faint hum in the background, but I suspect with such a long line a low level of that is inevitable.

I called BT earler, they did a manual test (I also did web based ones) with no fault found.

I eventually found an old analogue phone, direct to master test socket, and got the noise with 17070, called back to update the fault, and the agent heard the crackle.

They did another line test and at that point
- the noise stopped
- ADSL has returned to normal once reconnected (3837/940 on adsl2+)

I started making the BT callout arrangements then stopped at the point they read the "na fault found=charged" bit.

tricky. Guess I'll wait for reoccurance.

Any suggestions given that a test seems to clear the fault - for a bit at least?

I've had this previously, and then it's gone away for a week or more.
It seems to more often start/stop in office hours?

Usually the first indication of a problem is a dropped voip call or slow upload since I really never use the line to actally make calls....

Don't you have to report problems to O2 - especially as you are on LLU ?

RobertoS will be along in a minute to help as he LOVES O2

Voice (PSTN) faults should be reported to the line rental provider.
ADSL only faults to the broadband provider.
The OP probably has a line fault that may return.The wet weather may relevent. Best i.e. least agro regards possible no fault found charges, is to wait until it re-occurs then re-report. If the noise if present when talkig to the adviiser/customer service agent then insist they make a note of it on the report.

Aren't O2 doing some planned maintenance this week?

Yep, if it was broadband only I'd have to go via O2, but today it was a clear (not!) voice problem -- much much easier to report to bt...

Of course connection has been fine for the last few hours, since the last line test, so I'll have to wait for reoccurance.

Noise was evident on the call to CS, but not sure if it was noted.

Ok engineer came out today as arranged.

Turned out he's the team lead and worked this patch for years. After not find any problems initially after a while he heard the noise

Phew - no charge!

Ended up replacing cable between wires outside (underground) and master socket, as well as socket itself.

Advised that was a first step, and may address problem, but as the noise was intermittent I'd have to raise another problem if it returned and next time the likely action would be D/E side swap.

Apparently although our lines are very long (5km) they are generally in good condition and cause very few noise issues?

So a case of monitoring now. Good first step.

Note: This was a clear audio crackle issue - there was a knock-on effect of course on broadband.

Another update.

The noise returned later in the day for a few hours, then went again. I called BT to re-report and had an appt for later in the week.
Tue/Wed was clean

Thu the engineer came and, as they stated last time, proceeded to swap my E-side. Although this was a voice issue (audible crackle) I did explain I was worried about ADSL and getting poorer speed. The BT guy assured me that they're required to provide a line which measures as-good or better.

I should add that whatever online notes the BT guys had, they were not as good as my notes, including the name of the Bt engineer that had previously attended, and whom the new guy called to discuss actions taken so far & next steps. He was appreciative since it saved him lots of time.

BT guy disappears for a couple of hours (it was over lunch), comes back & let's me know it's all working, it just took quite a while to find a good quiet line. Apparently whilst the oiginal guy had said the lines were good, this guy suggested they weren't that good!

Now up/running & stable since Thursday. Speed very similar to before - perhaps a teeny bit lower downstream & teeny bit higher upstream (maybe 10% either way).

Interestingly my "step functions" in SNR have gone (up to 5dB) to be replaced by just a gradual day/night drift of around 2-2.5dB. Not that I'd ever noticed audible noise just because of this, so hadn't been able to report as a line fault.

If problem re-occurs their next step is a D-side swap. Apparently this requires a different "underground" engineer due to the cabling
Finger's crossed. Just need to wait....

Edited by planetf1 (Mon 19-Oct-09 13:25:51)

quick update. Line now stable for >1 week.